1. Technical Field
Embodiments of the present disclosure may generally relate to semiconductor devices, and more particularly, semiconductor device(s) relating to a refresh operation.
2. Related Art
Each semiconductor device, such as dynamic random access memory (DRAM) devices, may include a plurality of memory cells for storing data. Each DRAM cell of the DRAM devices may be configured to include a cell capacitor and a cell transistor. The DRAM devices may store data therein by discharging or charging the cell capacitors. Once the cell capacitor is charged or discharged to store a datum therein, an amount of electric charge stored in the cell capacitor has to be ideally constant even though time elapses. However, the amount of electric charges stored in the cell capacitor may actually vary because of a voltage difference between the cell capacitor and a circuit adjacent to the cell capacitor or because of a leakage current of the cell capacitor. In particular, if the amount of electric charges stored in the cell capacitor is reduced, the cell capacitor may lose a datum stored therein. This can cause malfunction of the DRAM device. Thus, the DRAM devices may require a refresh operation to prevent the memory cells from losing their data.
As semiconductor devices become more highly integrated with the development of process technologies, a distance between the memory cells as well as a distance between word lines connected to the memory cells is continuously reduced. If a distance between the word lines is reduced, data stored in the adjacent memory cells may be changed due to a coupling phenomenon or an interference phenomenon between the word lines.
Recently, an addition refresh scheme has been applied to a word line adjacent to a target word line, which is frequently accessed or activated, in order to prevent the memory cells connected to the word line adjacent to the target word line from losing their data due to the interference phenomenon between the word lines. The addition refresh scheme applied to the word line adjacent to the activated target word line is referred to as smart refresh.